The invention relates to a device for supplying hot water, in particular for the preparation of a drink, comprising a reservoir with heating unit with which a quantity of water in the reservoir is kept at a desired temperature, and a control unit which controls the heating unit depending on signals supplied by a temperature sensor present at or in the reservoir.
Such devices are known in various embodiments. In said known devices, the combination of control unit and temperature sensor is generally embodied in the form of a relatively simple thermostatic circuit which is used to keep the water in the reservoir at the desired temperature. This thermostatic circuit is adjusted by the manufacturer to a particular temperature value and cannot thereafter be altered by the user, at least not in a simple manner. In said devices the temperature of the water is preferably maintained below the boiling point in order to reduce the power consumption by the heating unit as much as possible. In a device for the preparation of a drink, such as coffee-making machine, the temperature will, for example, be adjusted to 98.degree. C. so that the water is maintained just below the boiling point temperature of approximately 100.degree. C. If the device is used, however, at a fairly high geographical altitude, for example in mountainous regions and the like, then the boiling point temperature of water on the site will be much lower, in particular it may be lower than 98.degree. C., which has been taken as an example in the above, with the result that the heating unit remains continuously switched on, the water is kept on the boil and much electrical power is wasted.
Until now it has been usual, if it is known that the device concerned has to operate at a fairly high geographical altitude at which the boiling point temperature of water is less than 100.degree. C., to adjust the thermostat in a manner such that the water in the reservoir just fails to start to boil. This means, however, a special adjustment of the thermostat at the manufacturer's premises for each customer, as a result of which the manufacturing process is impeded.